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New Scientist Live

Hubble repair may prove too costly

By Maggie McKee, Washington, DC

Repairing the Hubble Space Telescope may not be worth the cost if NASA siphons the money away from other science programmes, astronomers told a US congressional committee on Wednesday. But they argued NASA should mount a repair mission if it takes the money from its shuttle programme, as it has in the past.

The 14-year-old telescope is expected to become completely useless unless it receives new batteries and gyroscopes by 2009. But how NASA will install those components – and possibly two new science instruments that are already built – has been a source of controversy since January 2004.

That is when the agency cancelled a planned &dollar;350 million shuttle-based repair mission, citing safety risks in the wake of the Columbia disaster. NASA later vowed to pursue robotic repair, even after a National Academy of Sciences report argued for an astronaut fix. NASA also endorsed the study of yet another option, called “rehosting”. That involves launching the two new science instruments on a Hubble replacement.

But all of these options are pricey – estimated to cost &dollar;1-2 billion. And recent media reports say none of them are included in NASA’s 2006 budget, which will be made public on 7 February. Six experts from academia and industry weighed up the option at the hearing of the US Congress’s Science Committee.

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A number of those experts expressed concern that much or all of the money required would be taken from NASA’s science funding, following accounting changes within the last two years that oblige each programme to pay for the activities that support it. All four previous servicing missions to Hubble were almost entirely paid for with cash from the shuttle programme’s coffers.

Shift in accounting

“The method of cost accounting has shifted by a large amount,” says Joseph Taylor, a physicist at Princeton University in New Jersey, US, and co-chair of a National Research Council (NRC) committee that helps set national research priorities for astronomy every 10 years.

NASA “should surely do a servicing mission” if it took less than &dollar;400 million from the science budget, he told the hearing. But for missions that take &dollar;1 billion or more from science, the benefit of a Hubble fix is “not as clear”, he says. Taylor says he does not support any plan that “would require major delays or re-ordering of the NRC’s science priorities”. These include developing future X-ray and infrared space telescopes.

Sherwood Boehlert, chairman of the congressional science committee, agrees. “We have to make hard choices about whether a Hubble mission is worth it now, when moving ahead is likely to have an adverse impact on other programmes, including quite possibly other programmes in astronomy,” he says.

Disappearing money

But committee member Bart Gordon cited testimony from NASA’s chief, Sean O’Keefe, in 2002 suggesting that a shuttle servicing mission would not be paid for from the science budget. At that time, O’Keefe said the mission was included in NASA’s five-year spaceflight budget.

“Where did that money go?” Gordon asked. “Is NASA management now planning to walk away from its earlier budgetary commitment to the NASA science programme on the allocation of Hubble servicing costs?”

The science committee will hold a hearing with NASA about its 2006 budget on 17 February. At that point, says Boehlert, it will ask where NASA plans to take the money for any servicing mission. Boehlert says he is a “cheerleader” for the President George W Bush’s plan to return astronauts to the Moon and beyond. “But not if it means we decimate the budgets for science,” he told New Scientist.

Congress has ultimate control of NASA’s purse strings, and Boehlert says it will rule on a Hubble mission later in 2005.

Wednesday’s meeting crackled at times with dissent over the merits of each option. But no one responded when a committee member asked if anyone favoured simply scrapping Hubble – foregoing servicing entirely and proceeding with a planned mission to “de-orbit” the telescope in 2013.

“We must save Hubble’s science with any of the three options,” says Colin Norman, an astronomer at Johns Hopkins University, Baltimore, US, who testified in favour of a rehosting mission.